Influence of Ar/H2 ratio on the characteristics of phosphorus-doped hydrogenated nanocrystalline silicon films prepared by electron cyclotron resonance plasma-enhanced chemical vapor deposition

Phosphorus-doped hydrogenated nanocrystalline silicon films (nc-Si(P):H) were prepared by electron cyclotron resonance plasma-enhanced chemical vapor deposition. The effect of Ar/H2 ratio on the characteristics of as-grown nc-Si(P):H films was investigated systematically with Raman scattering, Hall effect measurements as well as Fourier Transform infrared spectroscopy (FTIR). The results indicated that the Ar/H2 ratio played a critical role for the crystalline quality and electrical properties of the nc-Si:H films. FTIR also showed that infrared spectrum intensity of SiH2 bonding mode peak decreased when Ar/H2 ratio increased. The optimal value Ar/H2 ratio of 10/15 was obtained for high quality nc-Si(P):H films with high electron density and the mechanism was elucidated in terms of Raman and FTIR analysis.